import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.Buffer;

public class unofibonacci {

	
	public static void main(String[] args) throws IOException {
		int n1;
		String frase = "";
		System.out.println("digite numero - la serie esta definida 1 1 2 3 5 8pero se toma como ");
		BufferedReader opcion = new BufferedReader(new InputStreamReader(System.in));
		frase = opcion.readLine();
		n1 = Integer.parseInt(frase);
		int r = fib(n1);
		System.out.println(r);

	}

	public static int fib(int n1) {

		if ((n1 == 0) || (n1==1)) {
			return 1;
		}
		else {
			return ((fib(n1-2)) + (fib(n1-1)));
		}

	}

}
	
	
